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arXiv · 1103.3516

Discretized Thermal Green's Functions

Mats Granath·Andro Sabashvili·Hugo U. R. Strand·Stellan Östlund
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Abstract

We present a spectral weight conserving formalism for Fermionic thermal Green's functions that are discretized in imaginary time and thus periodic in imaginary ("Matsubara") frequency. The formalism requires a generalization of the Dyson equation and the Baym-Kadanoff-Luttinger-Ward functional for the free energy. A conformal transformation is used to analytically continue the periodized Matsubara Green's function to the continuous real axis in a way that conserves the discontinuity at t=0 of the corresponding real-time Green's function. For given discretization the method allows numerical Green's function calculations of very high precision and it appears to give a well controlled convergent approximation as we decrease the discretization interval. The ideas are tested on Dynamical Mean Field Theory calculations of the paramagnetic Hubbard model.

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Mats Granath, Andro Sabashvili, Hugo U. R. Strand, Stellan Östlund. 2011-06-17. Discretized Thermal Green's Functions. https://doi.org/10.1002/andp.201100262

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